[alsa-devel] Channel map API patches: to be 3.7 or not to be?

Clemens Ladisch clemens at ladisch.de
Tue Sep 11 14:19:49 CEST 2012

Takashi Iwai wrote:
> BTW, this reminds me of an open question:
>   is it useful to add SND_CHMAP_MONO, or is it just redundant?
> It's nothing but indicating a mono channel without any channel
> position, so I supposed SND_CHMAP_UNKNOWN being sufficient.  OTOH,
> SND_CHMAP_MONO would give a clear sign of mono streams while
> SND_CHMAP_UNKNOWN could be used for any other exceptional purposes.

What would it be used for?

Labeling surround channels is necessary for reordering them or for doing
up/downmixing.  A "mono" channel, however, does not appear to have any
semantic difference from a single "unknown" channel.


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